Have you used your clarity settings? I'm trapped on +1. 0 Isn't worth my time. Which makes me think it's not a true line out. Could just be my equipment though.

I'm wondering how you would compare the sound to your clip.

All in all it definitely improves sound quality, and it's pretty much a must if you appreciate sound in general.

I'm not surprised you like clarity settings on 1. My Cmoy (which uses a LME49860 op amp) adds a lot of brightness to the sound (treble basically) so it sounds somewhat similar to having the clarity settings on, but marginally better.

The FiiO (I haven't heard the E5 mind, but I have the E3) adds bass and rolls off the treble, making the sound a little darker. So clarity settings would counter-act this, I guess

Its not that one sounds is better or worse, just a matter of personal taste.

Although it seems unlikely it really is true line out, because sound straight from a DAC shouldn't have effects / EQs & stuff on it, MP3 player circuits are realistically much more complicated than a simple MP3 > DAC > AMP set up. Difference chips serve multiple functions, DACs have amps built in, and all kinds of crazy crap!

Somtimes ago I bought a docking station for my P2. This was made for an old Yepp and didn't work with my P2.

Reading this thread I thought it would be an good idea to reconstruct this dock for my current P3.
I opened it by screwing the for screws hidden by the four rubber feets and it contained a small circuit board beeing connected to the proprietary Samsung connector at the top of the dock by a couple of seperated cables.
At the circuit board there are a Samsung connector and a line out connector solded.
I believe that it should be possible to make a usable dock from this.

I would add a standard USB mini port and keep the proprietary Samsung simply routed through.
An amplifier for real line out voltage level should be added, too, but this is more than I could work out.

Any idea what this would sound like without an amp? I ask because my jack is starting to not recognize my headphones. It'll randomly pause and I'll have to unlock it, hit play, and lock it again, and this'll happen every 30 seconds or so if I'm moving. I don't want to carry around an amp with me, and I have low impedance headphones (ATH-M50), so I was thinking maybe I could make an LOD cable with a female connector that I could plug my headphones directly into.

EDIT: I bought a spare cable and tried it and sure enough, it works, without an amp. I like the sound, but it's almost identical to the jack, so not much to say there. Just interesting that it works. I believe I've made the first LOD cable with a jack for headphones to plug directly into, aside from the fiio cord with the itty-bitty-amp-that-looks-like-a-volume-control built in.